ReviewPrevalence of Toxoplasma gondii infection among animals in Algeria: A systematic review and meta-analysis
Introduction
The protozoan Toxoplasma gondii is an obligate intracellular zoonotic parasite that can infect all warm-blooded animals worldwide. The parasite has only one definitive host, the felidae [1,2]. Intermediate hosts (humans and other animals) can be infected by eating food contaminated with oocysts eliminated by cats in their feces or by ingesting tissue cysts of the parasite after eating undercooked meat [1,3]. Congenital contamination occurs through the placenta in a first infected pregnant woman [3]. It has been suggested that consumption of contaminated unboiled and unpasteurized milk causes toxoplasmosis in humans [2]. The World Health Organization estimated that about 22 % of human T. gondii infections are meatborne [4].
The excretion of oocysts by the cat takes only 1−2 weeks, but millions of oocysts can be excreted. These oocysts can survive in the environment for several months and are substantially resistant to freezing, drying and disinfectants [5].
The infection is generally asymptomatic, but multiple disorders may be observed, including reproductive losses in animals and cognitive impairment and fatal encephalitis in humans [1]. In animals, the economic losses resulting from T. gondii infection are considerable and due to fetal death, abortion, neonatal death and mummification [6].
Various primary studies have been published in Algeria assessing the prevalence of T. gondii infection in animals. Combining the results of these studies using systematic and meta-analytic methods will be of great importance. To the best of our knowledge, no studies have been conducted on the overall prevalence and associated risk factors of T. gondii infection in animals in Algeria. Therefore, this systematic review and meta-analysis was conducted to determine the prevalence and to assess the associated risk factors of T. gondii infection in animals in Algeria over the past five years.
Section snippets
Search strategy
This systematic literature review was conducted to investigate the prevalence and risk factors associated with T. gondii infection in animals in Algeria. It was performed according to the recommendations of the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guideline [7]. Relevant studies were identified by searching five literature databases including PubMed, Thomson Reuters, ScienceDirect, Scopus and Google Scholar. The search criteria were specified in advance
General description of included studies
Among all five databases searched from 1955 to 2020, a total of 14 papers were eligible to be included in this systematic review and meta-analysis study. The 14 selected studies were concerned a number of 10,187 animals of which 2594 were positive cases (25.46 %) (24.62–26.31 %, 95 % IC). According to animal species, the total number of infected animals was 509 cattle, 762 sheep, 320 goats, 713 horses, 9 donkeys, 135 Stray cats, 51 local rabbits, 32 dogs, 61 chicken, 7 gooses and 4 ducks.
Linear
Discussion
Toxoplasmosis due to T. gondii is a very wide geographical distribution and is known to be one of the most frequent parasitic infections of man and other warm blooded animals [8,9]. This zoonosis parasite was studied in Algeria and demonstrating that its epidemiological cycle is very well maintained in the country.
The first study on toxoplasmosis in Algeria was published in 1955 [10] in dogs and since then no studies have been carried out until 2015.
The questions that led us to conduct this
Conclusion
Animal infection by T. gondii is well documented in most countries worldwide, but in Algeria, little information is available to quantify the impact on the livestock sector and public health. This meta-analysis indicates that Toxoplasma-infection appears not to be rare in Algeria. The difference could therefore be associated with age, gender, type of breeding, presence of cats, herd size and water quality. Further epidemiological studies are needed to clarify the design of regional strategies
Declaration of Competing Interest
The authors report no declarations of interest.
References (52)
- et al.
Toxoplasma gondii prevalence in farm animals in the United States
Int. J. Parasitol.
(2013) - et al.
Phylogeography of Toxoplasma gondii points to a South American origin
Infect. Genet. Evol.
(2017) - et al.
Toxoplasma and Africa: one parasite, two opposite population structures
Trends Parasitol.
(2018) - et al.
Prevalence and risk factors for Toxoplasma gondii infection in meat animals and meat products destined for human consumption
J. Food Prot.
(2015) - et al.
High seroprevalence of Toxoplasma gondii and probability of detecting tissue cysts in backyard laying hens compared with hens from large free-range farms
Int. J. Parasitol.
(2017) - et al.
Seroprevalence of Toxoplasma gondii infection in cattle, sheep, goats and pigs from the North of Portugal for human consumption
Vet. Parasitol.
(2013) - et al.
Toxoplasma gondii infections in dogs: 2009-2020
Vet. Parasitol.
(2020) - et al.
First genetic characterization of Toxoplasma gondii in stray cats from Algeria
Vet. Parasitol.
(2017) - et al.
Toxoplasma gondii infection and toxoplasmosis in farm animals: risk factors and economic impact
Food Waterborne Parasitol.
(2019) Toxoplasmosis - a waterborne zoonosis
Vet. Parasitol.
(2004)